» Articles » PMID: 33127411

Effects of Alfaxalone on Cerebral Blood Flow and Intrinsic Neural Activity of Rhesus Monkeys: A Comparison Study with Ketamine

Overview
Publisher Elsevier
Specialty Radiology
Date 2020 Oct 31
PMID 33127411
Citations 4
Authors
Affiliations
Soon will be listed here.
Abstract

Objective: Alfaxalone has been used increasingly in biomedical research and veterinary medicine of large animals in recent years. However, its effects on the cerebral blood flow (CBF) physiology and intrinsic neuronal activity of anesthetized brains remain poorly understood.

Methods: Four healthy adult rhesus monkeys were anesthetized initially with alfaxalone (0.125 mg/kg/min) or ketamine (1.6 mg/kg/min) for 50 min, then administrated with 0.8% isoflurane for 60 min. Heart rates, breathing beats, and blood pressures were continuously monitored. CBF data were collected using pseudo-continuous arterial spin-labeling (pCASL) MRI technique and rsfMRI data were collected using single-shot EPI sequence for each anesthetic.

Results: Both the heart rates and mean arterial pressure (MAP) remained more stable during alfaxalone infusion than those during ketamine administration. Alfaxalone reduced CBF substantially compared to ketamine anesthesia (grey matter, 65 ± 22 vs. 179 ± 38 ml/100g/min, p<0.001; white matter, 14 ± 7 vs. 26 ± 6 ml/100g/min, p < 0.05); In addition, CBF increase was seen in all selected cortical and subcortical regions of alfaxalone-pretreated monkey brains during isoflurane exposure, very different from the findings in isoflurane-exposed monkeys pretreated with ketamine. Also, alfaxalone showed suppression effects on functional connectivity of the monkey brain similar to ketamine.

Conclusion: Alfaxalone showed strong suppression effects on CBF of the monkey brain.The residual effect of alfaxalone on CBF of isoflurane-exposed brains was evident and monotonous in all the examined brain regions when used as induction agent for inhalational anesthesia. In particular, alfaxalone showed similar suppression effect on intrinsic neuronal activity of the brain in comparison with ketamine. These findings suggest alfaxalone can be a good alternative to veterinary anesthesia in neuroimaging examination of large animal models. However, its effects on CBF and functional connectivity should be considered.

Citing Articles

Magnetic resonance imaging of the monkey fetal brain in utero.

Zhang X Investig Magn Reson Imaging. 2023; 26(4):177-190.

PMID: 36937817 PMC: 10019598. DOI: 10.13104/imri.2022.26.4.177.


Development, refinement, and characterization of a nonhuman primate critical care environment.

Bozzay J, Walker P, Atwood R, DeSpain R, Parker W, Chertow D PLoS One. 2023; 18(3):e0281548.

PMID: 36930612 PMC: 10022766. DOI: 10.1371/journal.pone.0281548.


Effects of Anesthesia on Cerebral Blood Flow and Functional Connectivity of Nonhuman Primates.

Zhang X Vet Sci. 2022; 9(10).

PMID: 36288129 PMC: 9609818. DOI: 10.3390/vetsci9100516.


Synthetic neuroactive steroids as new sedatives and anaesthetics: Back to the future.

Manzella F, Covey D, Jevtovic-Todorovic V, Todorovic S J Neuroendocrinol. 2022; 34(2):e13086.

PMID: 35014105 PMC: 8866223. DOI: 10.1111/jne.13086.


Altered hippocampal-prefrontal functional network integrity in adult macaque monkeys with neonatal hippocampal lesions.

Li C, Li Z, Hu X, Zhang X, Bachevalier J Neuroimage. 2020; 227():117645.

PMID: 33338613 PMC: 11731401. DOI: 10.1016/j.neuroimage.2020.117645.

References
1.
Silva A, Paiva F . Dynamic magnetic resonance imaging of cerebral blood flow using arterial spin labeling. Methods Mol Biol. 2008; 489:277-95. PMC: 4748953. DOI: 10.1007/978-1-59745-543-5_13. View

2.
Liu X, Zhang N, Chang C, Duyn J . Co-activation patterns in resting-state fMRI signals. Neuroimage. 2018; 180(Pt B):485-494. PMC: 6082734. DOI: 10.1016/j.neuroimage.2018.01.041. View

3.
Dhasmana K, Saxena P, Prakash O, Van der Zee H . A study on the influence of ketamine on systemic and regional haemodynamics in conscious rabbits. Arch Int Pharmacodyn Ther. 1984; 269(2):323-34. View

4.
Oren R, Rasool N, Rubinstein E . Effect of ketamine on cerebral cortical blood flow and metabolism in rabbits. Stroke. 1987; 18(2):441-4. DOI: 10.1161/01.str.18.2.441. View

5.
Li C, Zhang X . Effects of Long-Duration Administration of 1% Isoflurane on Resting Cerebral Blood Flow and Default Mode Network in Macaque Monkeys. Brain Connect. 2016; 7(2):98-105. PMC: 5359674. DOI: 10.1089/brain.2016.0445. View